Cummins/Onan — Angular Alignment Procedure
Adjustments · Generator/engine coupling
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DFJA, Cummins/Onan DFJB, Cummins/Onan DFJC, Cummins/Onan DFJD, Cummins/Onan KTA38-G1 engine, Cummins/Onan KTA38-G2 engine, Cummins/Onan KTA38-G3 engine, Cummins/Onan KTA38-G4(G5) engine
Before you start
- Accidental starting of the generator set during this procedure presents the hazard of severe personal injury or death. Disconnect the negative (-) battery cable(s) before beginning.
Procedure
- Disconnect negative (-) battery cable(s) before beginning.
- Fasten a dial indicator to either the generator shaft or the cooling fan with the sensing point on the capscrew head or flat surface of the drive disc at the bolt circle diameter.
- Bar the engine over in a clockwise rotation as viewed from the engine flywheel; do not allow it to roll back on compression.
- T.I.R. is the sum of the maximum positive and negative dial indicator readings as the engine completes one revolution.
- To correct, remove equal shims from under both generator mounting feet.
- Measure distance from generator shaft center to the indicator measuring point.
- Measure distance from generator side of flex discs to center of generator mounting bolt.
- Compare the two distances to get a ratio; multiply the ratio by one half the T.I.R. to get the shim amount to remove.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Sample T.I.R. 0.025 in
- T.I.R. should not be more than 0.001 in for each inch of radius
Full service-parts list: Cummins/Onan DFJA →, Cummins/Onan DFJB →, Cummins/Onan DFJC →, Cummins/Onan DFJD →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.